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Serrated edges on all cuts on hdpe. Did not change feed and speeds which have been working fine (some serration of edges but usually only in curves and even then not to this degree). Checked square of table, level of table and rack. Checked how bearings ride on rails as it rides along the X. Tried to troubleshoot as mentioned in other forum posts and from Shopbot files.
Has a blower motor attached for vacuum. Parts hold down well to table. Clamped sheet to make sure. Same result.
According to operator, machine ran really rough one day on a file we had run previously with no issue. Since then we have not been able to eliminate this serration when cutting in the X.
Only change was new pinion gears. Put old ones back on same result. Thought it might be a motor issue so we switched X motor with Y and Z for same result.IMG_4530.jpgIMG_4537.jpg
PRS Alpha 48 x 96
HSD Spindle
ATC

Be sure you've set the pinion gears tight enough. That's what it looks like to me. Since you're pushing them up to get them set, it can take a lot of force to overcome the weight of the motor and get them situated correctly.

Try contacting Gary Campbell or Brady on here and see if they would be willing to come fix it. You will probably save money in the long run paying one of these guys to come to your shop if they are willing.

Set pinions into rack with a scale to make sure we have recommended pressure into rack. What is curious is I only get this serration in the X axis not in the Y.
Ran motors off the rack, checked for run out and they seem fine. There is a minute amount of play in the shaft which lead me to believe the motors could be an issue. Swapped X motors for Y and Z got same result but I did not use scale to set them into rack during that swap. Got a new 6 foot level and made sure level of table and rack is spot on. There was a small amount of adjustment needed there. Still searching...Would be great if there was someone closer than Durham, NC that could help...

Tried the suggestions but have not come up with a solution to the X-axis chatter issue.
There is an issue that sticks in my head and makes me think it could be the X motors. I was told by our current machine operator that the former operator (not with the company any longer and not reachable for a conversation) used a bottle jack to engage the pinion into the rack. He said the X motors were really cranked into place. This may have fixed whatever that operator was experiencing at the time but could have been not a good thing for the motors longer term. When I take the motors off there is a small amount of play in the shaft but I thought I was being hypersensitive and looking for anything to explain this chatter I could not fix. A negative to this theory is when I switched the X motors with the Y and Z I still got the chatter but now I questioning whether I ran the experiment under the same conditions.
If any one local to NE Ohio or beyond is up for a site visit to provide a second set of eyes we can certainly negotiate something equitable for all.

You really have to push the X motors into place. A bottle jack, if done to the extreme, could overtax the motors and damage them though. Brady would probably be a good one to comment on the exact amount of force required to correctly set those motors. I used a pressing clamp to set mine. It's made out of plastic and not that powerful but it does exert a constant force and did the trick. The motors are heavy and fight back.

Be sure to grease your rack too. Doing that takes a bit of slop out of the system but certainly not to the level you're seeing now.